There is a reason why this film is unknown and forgotten. "Nattlek" is quite bad. It is not as good as Mai Zetterling's "Älskande Par" or "the Girls" (which I consider as the best Swedish film ever made).
I was looking forward to seeing this film. It was released on DVD in Sweden, so I jumped at the chance to watch it. It sounded good, or at least interesting. Ingrid Thulin, who was always a good actress, was typecast here as a neurotic mother to a little boy, (reminds me of the decadence in "the Damned" by Visconti). When the boy is an adult he takes with him his girlfriend to the castle where he grew up and they face his childhood demons.
The girlfriend played by fresh faced Lena Brundin gives the film some humanity but she has to play opposite Keve Hjelm who is very dull and plays his role in the pretentious acting style people back then thought was serious and worthy. Famous Swedish jazz singer Monica Zetterlund livens things up but has a too brief part in this film.
Crazy party guests and relatives try to give the film a feeling of Fellini and Bergman without any feeling or depth. Borrowing fashionable ingredients from other films does not an art-house classic make. The film is interesting to watch as a document of its time. The arty psychodrama films went out of style. This type of film killed itself.